<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    body {
      background: url(pic/04.jpg) no-repeat top center / cover;
    }
  </style>
</head>

<body>
  <script>
    // console.dir(document.body)
    //刷新页面随机背景图片
    function getRandom(N, M) {
      return Math.floor(Math.random() * (M - N + 1)) + N
    }
    const random = getRandom(1, 10)
    document.body.style.backgroundImage = `url(pic/${random}.jpg)`
  </script>
</body>

</html>